Vehicle seat assemblies come in a wide variety of shapes and sizes. Many vehicle seat assemblies currently include integrated front seat belts. Such assemblies eliminate the need to anchor the shoulder belts to a pillar between the front and rear windows, instead containing the entire belt apparatus within the seat. Some advantages of such integrated seat belts is that they eliminate unsightly shoulder belts hooked to the pillars and also improves entry and exit in some vehicles. The integrated belts also make it easier to remove the second and third rows of seats in minivans. Furthermore, such integrated seat belts are generally more comfortable because the belts move with the seat.
Vehicle seat assemblies including occupant sensing systems are well known. One method for the automatic adjustment of headrest height involves active transducers (i.e. ultrasound or infrared light-emitter transmitter and receiver pairs). The transmitters emit non-visible waves and receivers at various locations sense the reflected or interrupted signal from the head of the occupant.
For example, the U.S. patent to Bruse et al. U.S. Pat. No. 4,645,233 discloses an adjustment mechanism for automatically adjusting the height of a headrest of vehicle seat wherein a sensor detects the seating height of a person seated on the vehicle seat in a normal position and controls a motor for the height adjustment of the headrest in accordance with detection results. In one embodiment, one light emitter-receiver is located in the upper area of the front side of a headrest, while another light emitter-receiver detects the height of a shoulder of the person.
Another vehicle seat assembly including an occupant sensing system is disclosed in the U.S. patent to Bauer U.S. Pat. No. 5,431,447. Sensors generate signals which are processed by a microcomputer and to, in turn, generate a control signal which actuates a motor in a seat belt restraint system. The sensors sense characteristics of an occupant such as weight and location of the occupant in the vehicle.
Other vehicle seat assemblies include occupant sensing systems in order to generate a control signal which can be used by an air bag actuation circuit to inhibit air bag deployment. When one or more air bags are provided in an automobile, the air bag may be stored in many different locations such as in a steering wheel, in a seat bolster, a door panel or in an instrument panel of the vehicle.
Such systems are desirable and are often times preferred over occupant sensing systems mounted in front of the vehicle occupant. Mounting an occupant position sensor in front of a vehicle occupant or to the side of the occupant may provide a false reading because of an object placed between the position sensor and the occupant. For example, the object may be the hand of the vehicle occupant, the crossed legs of the occupant, or a map or the like held between the position sensor and the occupant.
The U.S. patent to Steffens, Jr. et al. U.S. Pat. No. 5,439,249 discloses a vehicle seat assembly including an occupant sensing system having a sensor mounted in the seat back. Preferably, the sensor is an ultrasonic sensor having a sound beam.
The U.S. patent to Mattes et al. U.S. Pat. No. 5,118,134 discloses a vehicle seat assembly including an occupant sensing system having a position sensor in the headrest of the vehicle seat. The position sensor has at least one light transmitter and one light receiver.
The U.S. patent to Fujita et al. U.S. Pat. No. 5,074,583 discloses a vehicle seat assembly including an occupant sensing system including a plurality of pressure sensors having a spaced relationship relative to one another to detect pressure acting on the seat back and seat cushion. The sensors typically are electrostatic capacitance sensors to detect a pressure distribution across the seat device in order to provide a control signal for an air bag system.
The U.S. patent to Schousek U.S. Pat. No. 5,474,327 discloses a vehicle seat assembly including an air bag restraint system wherein air bag deployment is inhibited when an occupied, rear-facing infant seat is present. The sensing apparatus comprises eight variable resistance pressure sensors located in a seat cushion.
The U.S. patent to Steffens, Jr. et al. U.S. Pat. No. 5,413,378 also discloses a vehicle seat assembly including an occupant sensing system having an occupant position sensor which takes the form of an ultrasonic sensor.
U.S. Pat. Nos. 5,071,160; 5,232,243; 5,366,241; 5,398,185; and 5,400,487 all discloses passenger seat detecting and position determining sensors for controlling passive restraint systems including air bags in vehicles.
U.S. Pat. No. 4,834,420 discloses an air bag-equipped child seat.